/*
 * Licensed to Metamarkets Group Inc. (Metamarkets) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Metamarkets licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package io.druid.query.groupby.epinephelinae;

import com.google.common.primitives.Ints;

import java.nio.ByteBuffer;
import java.util.Comparator;

public class IntKeySerde implements Grouper.KeySerde<Integer>
{
  public static final Grouper.KeySerde<Integer> INSTANCE = new IntKeySerde();

  private IntKeySerde()
  {
    // No instantiation
  }

  private static final Grouper.KeyComparator KEY_COMPARATOR = new Grouper.KeyComparator()
  {
    @Override
    public int compare(ByteBuffer lhsBuffer, ByteBuffer rhsBuffer, int lhsPosition, int rhsPosition)
    {
      return Ints.compare(lhsBuffer.getInt(lhsPosition), rhsBuffer.getInt(rhsPosition));
    }
  };

  private static final Comparator<Grouper.Entry<Integer>> ENTRY_COMPARATOR = new Comparator<Grouper.Entry<Integer>>()
  {
    @Override
    public int compare(Grouper.Entry<Integer> o1, Grouper.Entry<Integer> o2)
    {
      return o1.getKey().intValue() - o2.getKey().intValue();
    }
  };

  private final ByteBuffer buf = ByteBuffer.allocate(Ints.BYTES);

  @Override
  public int keySize()
  {
    return Ints.BYTES;
  }

  @Override
  public Class<Integer> keyClazz()
  {
    return Integer.class;
  }

  @Override
  public ByteBuffer toByteBuffer(Integer key)
  {
    buf.putInt(0, key);
    buf.position(0);
    return buf;
  }

  @Override
  public Integer fromByteBuffer(ByteBuffer buffer, int position)
  {
    return buffer.getInt(position);
  }

  @Override
  public Grouper.KeyComparator bufferComparator()
  {
    return KEY_COMPARATOR;
  }

  @Override
  public void reset()
  {
    // Nothing to do
  }
}
